Experimental Test of Relativistic Time Dilation by Laser Spectroscopy of Fast Ions

The present thesis deals with a modern version of the classical Ives-Stilwell experiment, which measures relativistic time dilation via the transverse Doppler effect. A deviation from the prediction given by Special Relativity would disprove the Relativity Principle and, therefore, single out a physically preferred reference frame. In order to enhance the accuracy of previous experiments in this sector, the systematics of two Doppler-free techniques of collinear laser spectroscopy on a fast (v=0.064c) ion beam in a storage ring have been investigated. The first technique, Lambda-spectroscopy on a closed Lambda-type three-level system, suffered from a strong, hitherto unaccounted line broadening in a previous test experiment. In this work this line broadening has been shown to be caused by processes changing the velocity of the ions during several to many roundtrips in the storage ring. Additionally, a method has been developed to supress this broadening. The second technique investigated is saturation spectroscopy, which turned out to be insensitive to velocity-changing processes. Together with the reduction of systematic errors the application of saturation spectroscopy has lead to a new upper limit for deviations from special relativistic time dilation, that improves the hitherto best value by a factor of 4

Test of Time Dilation Using Stored Li+ Ions as Clocks at Relativistic Speed

We present the concluding result from an Ives-Stilwell-type time dilation experiment using 7Li+ ions confined at a velocity of beta = v/c = 0.338 in the storage ring ESR at Darmstadt. A Lambda-type three-level system within the hyperfine structure of the 7Li+ triplet S1-P2 line is driven by two laser beams aligned parallel and antiparallel relative to the ion beam. The lasers' Doppler shifted frequencies required for resonance are measured with an accuracy of < 4 ppb using optical-optical double resonance spectroscopy. This allows us to verify the Special Relativity relation between the time dilation factor gamma and the velocity beta to within 2.3 ppb at this velocity. The result, which is singled out by a high boost velocity beta, is also interpreted within Lorentz Invariance violating test theories

Feasibility of Coherent xuv Spectroscopy on the 1S-2S Transition in Singly Ionized Helium

The 1S-2S two-photon transition in singly ionized helium is a highly interesting candidate for precision tests of bound-state quantum electrodynamics (QED). With the recent advent of extreme ultraviolet frequency combs, highly coherent quasi-continuous-wave light sources at 61 nm have become available, and precision spectroscopy of this transition now comes into reach for the first time. We discuss quantitatively the feasibility of such an experiment by analyzing excitation and ionization rates, propose an experimental scheme, and explore the potential for QED tests

Improved test of time dilation in special relativity

An improved test of time dilation in special relativity has been performed using laser spectroscopy on fast ions at the heavy-ion storage-ring TSR in Heidelberg. The Doppler-shifted frequencies of a two-level transition in 7Li+ ions at v=0.064c have been measured in the forward and backward direction to an accuracy of Deltanu/nu=1 x 10(-9) using collinear saturation spectroscopy. The result confirms the relativistic Doppler formula and sets a new limit of 2.2 x 10(-7) for deviations from the time dilation factor gamma(SR)=(1-v2/c2)(-1/2)

ARTICLES Test of relativistic time dilation with fast optical atomic clocks at different velocities

Time dilation is one of the most fascinating aspects of special relativity as it abolishes the notion of absolute time. It was first observed experimentally by Ives and Stilwell in 1938 using the Doppler effect. Here we report on a method, based on fast optical atomic clocks with large, but different Lorentz boosts, that tests relativistic time dilation with unprecedented precision. The approach combines ion storage and cooling with optical frequency counting using a frequency comb. 7 Li + ions are prepared at 6.4 % and 3.0 % of the speed of light in a storage ring, and their time is read with an accuracy of 2×10 −10 using laser saturation spectroscopy. The comparison of the Doppler shifts yields a time dilation measurement represented by a Mansouri–Sexl parameter | ˆα | ≤ 8.4×10 −8, consistent with special relativity. This constrains the existence of a preferred cosmological reference frame and CPT- and Lorentz-violating ‘new ’ physics beyond the standard model. Since its introduction by Albert Einstein in 1905 (ref. 1), special relativity has been the accepted theory of local space-time. It not only resolved severe open questions in electrodynamics but introduced a revolutionary new notion of space and time that influenced a variety of areas from technology 2 to philosophy 3. Today its main ingredient, the space-time symmetry of local Lorentz invariance, is deeply woven into all physical theorie